1. Field of the Invention
The present invention relates to intake valves, and more particularly to an automatic air intake valve in an internal combustion engine with self-cleaning feature for removing hydrocarbon deposits.
2. Description of the Background
The present invention relates to intake valves used in an internal combustion engine. FIGS. 1-8 diagrammatically depict the cycle of an internal combustion engine. As shown in FIG. 1, the components of the internal combustion engine generally comprises an engine block 10 having a plurality of cylinders 12. Each cylinder 12 houses a piston 14 connected to a crankshaft 16 via a piston rod 18 as is commonly known to those skilled in the art. Each cylinder includes an intake valve 20 for admitting air prior to the compression event, and an exhaust valve 22 for venting exhaust fumes following the compression event. Exhaust valve 22 may alternatively be an exhaust port positioned along a sidewall of cylinder 12 as more fully described in U.S. Pat. No. 6,257,180 to Klein. The particular type of intake valve 20 shown in FIG. 1 is a pressure responsive automatic air intake valve for use in a forced coaxially ventilated two stroke or four power plant. Such a valve opens and closes in response to differences in air pressure between the intake manifold and the combustion chamber (cylinder).
For illustrative purposes, the four stroke engine cycle can be broken down into seven sequential events, each event corresponding to a specific position of the piston 14, intake valve 20 and exhaust valve 22.
As shown in FIG. 1, the cycle begins with piston 14 at the top dead center position within cylinder 12. Both intake valve 20 and exhaust valve 22 are in the closed position.
FIG. 2 shows the second position or xe2x80x9cintakexe2x80x9d wherein piston 14 travels downwardly through cylinder 12, and intake valve 20 opens allowing air to be inducted into the chamber of cylinder 12.
FIG. 3 represents the next distinct step in the engine cycle wherein piston 14 reaches bottom dead center in cylinder 12 and intake valve 20 closes again.
FIG. 4 shows the xe2x80x9ccompressionxe2x80x9d stage wherein piston 14 moves upwardly through cylinder 12 compressing the mixture of air and gas in the cylinder. Both intake valve 20 and exhaust valve 22 remain in the closed position.
FIG. 5 shows the xe2x80x9cpowerxe2x80x9d stage in which piston 14 is driven downward once again through chamber 12, until it reaches bottom dead center as shown in FIG. 6. FIG. 7 shows the next sequential stage or the xe2x80x9cexhaustxe2x80x9d stage wherein piston 14 travels once more upwardly through cylinder 12, and exhaust valve 22 opens allowing the accumulated exhaust gasses to be expelled from the chamber of the cylinder 12. As shown in FIG. 8, at the end of the xe2x80x9cexhaustxe2x80x9d stage piston 14 reaches top dead center once more, exhaust valve 22 closes, and the engine cycle repeats itself.
The cycle is known as the Otto Cycle and is well known by those skilled in the art as a means for generating power via an internal combustion engine.
The adherence of soot and impurities to the sidewall of the valves and surrounding surfaces is an unavoidable consequence of the combustion of hydrocarbon fuel. Over time, accumulated sootmight obstruct the proper opening and closing of the valve. The object of the instant invention is to overcome this drawback and to provide a self-cleaning valve assembly for removing the potentially fouling soot.
The problem of hydrocarbon build-up in the combustion chamber of engines such as the above is well known. Prior solutions, however, have been directed towards flushing away the accumulated soot deposits. For example, U.S. Pat. No. 6,178,944B I to Kerns et al. teaches a method wherein additional fuel is injected into the combustion chamber, drawn into the intake manifold and subsequently inducted back into the combustion chamber past the intake valve to flush carbon deposits from the intake valve and surrounding surfaces. Unfortunately, the cleaning method of Kerns et al. is inefficient because it requires certain steps in addition to the normal engine cycle. This in turn requires more internal engine parts, and more maintenance.
A second example is shown in U.S. Pat. No. 5,286,264 to Russo, et al. Russo ""264 teaches a gasoline detergent additive composition for flushing hydrocarbon deposits from internal engine components. Unfortunately, the detergent is only useful for removing hydrocarbon deposits after they have formed, rather than removing the fouling deposits as they form.
Absent from the prior art is a method for mechanically removing the accumulated hydrocarbon deposits from an engine valve. Accordingly, it would be advantageous to provide a self-cleaning engine valve and valve guide for mechanically removing hydrocarbon deposits. It further be advantageous to provide a self-cleaning engine valve for mechanically removing hydrocarbon deposits using the normal movement of an engine during the cycle of ventilation, compression, and combustion.
It is, therefore, an object of the present invention to provide a self-cleaning valve assembly for mechanically removing accumulated hydrocarbon deposits from the surface of the valve.
It is another object of the present invention to provide a self-cleaning valve assembly for mechanically removing accumulated hydrocarbon deposits from the valves of an internal combustion engine which uses the movement of the engine during the normal cycle of ventilation, compression, and combustion.
According to the present invention, the above-described and other objects are accomplished by providing a bushing which houses a reciprocating slider valve member. The inner walls of the bushing are fluted with small relief passages which run parallel (more or less) to the direction of the movement of the slider. As soot accumulates in the valve seat and side walls of the slider, it is collected in the flutes when the valve closes. Repeated closing of the valve hammers the soot higher into the fluted relief passages, while the vertical movement of the slider shears any soot which protrudes into its path from the flutes. The soot thereafter mixes with the intake air to be recombusted or wasted along with the portion of incoming air which cools the cylinder.